CASE REPORT

INTRODUCTION

CAD/CAM (computer-aided design/computer-aided

manufacturing) in implant dentistry has broadened their

application areas into treatment planning, implant

placement and restorations. Due to the multitude and

complexity of developing techniques, it is challenging to

choose the optimal method for each patient. Therefore, this

clinical report describes a method of restoring an edentulous

maxilla by means of a combination of several computer-

aided tools, such as SimPlant, SurgiGuide (Materialise,

Leuven, Belgium) and Procera (Nobel Biocare, Goteborg,

Sweden), as an approach to manage complex clinical cases.

CASE PRESENTATION

A 47 year-old female patient having fully edentulous

maxilla and partially edentulous mandible presented to the

Harvard School of Dental Medicine with the desire of a

fixed type of dental prosthesis. She presented with poorly

fitting maxillary and mandibular removable prostheses,

which lost retention even during normal conversations.

Furthermore, her remaining dentition was severely

compromised by periodontal disease and carious lesions.

The patient has been treated for hypertension for several

years, and it is currently controlled with Atenolol. She does

not present with any contraindications for elective surgical

procedures. A CT scan with a radiographic template and the

SimPlant software (Fig. 1) revealed severe generalized

alveolar ridge resorption in the maxilla, leaving minimal

space for implant placement. On the basis of the clinical and

radiographic evaluation, this patient was classified as a

Class IV partial edentulism (ACP PDI: American College

of Prosthodontics Prosthodontic Diagnostic Index).1

SURGICAL TREATMENT

The ideal treatment plan represents the most

comprehensive and desirable option of therapy and - in this

case at hand - includes implants and fixed prosthetic

restorations. In the first step, a radiographic template was

fabricated according to the diagnostic wax-up and a CT was

taken. Using the SimPlant software, future implant positions

and sizes were pre-planned taking anatomical landmarks

and the position of future prosthetic restorations into

account. The data were then sent via internet to Materialize

Inc. in Belgium, where bone supported surgical guides

(SurgiGuides) were fabricated according to the sent

SimPlant plan. SurgiGuide is produced on a 3-dimensional

stereolithographic model of the jaw. Sleeves in different

diameters are built in later serving as a precise 3-

dimensional guide for implant placement (Fig. 2). Four 3.75

×13 mm, one 5×11.5 mm, one 5×13 mm, and one 3.3×

11.5 mm implants (MkIII TiU, Nobel Biocare, Goteborg,

Sweden) were placed under two stage surgical protocols.

An implant could not be placed on the left central incisor

area due to insufficient bone width even though it was

expected to certain degree at the time of planning. After

uneventful healing stage, the prosthodontic phase of

treatment began approximately 4 month post-implant

placement.

634 J Korean Acad Prosthodont 2008 Vol 46 No 6

THE MANAGEMENT OF A COMPLEX IMPLANT CASE USINGCAD-CAM TECHNOLOGY: A CLINICAL REPORT

Eun-Jin Park*, DDS, MMSc, PhD

Assistant Professor, Department of Dentistry School of Medicine, Ewha Womans University

Corresponding Author: Eun-Jin Park

Dept. of Dentistry School of Medicine, Ewha Womans Univ.

911-1 Mok-6-dong, Yangcheon-gu, Seoul, Korea +82-2-2650-5042: e-mail, prosth@ewha.ac.kr

Received June 9, 2008 Last Revison July 4, 2008 Accepted July 21, 2008.

※ This work has been presented and won the best poster presentation award at the fall meeting of the Korean Academy of

Prosthodontics, Seoul, KOREA, Nov. 2007.

DOI:10.4047/jkap.2008.46.6.634

The management of a complex implant case using CAD-CAM technology: A clinical report EJ Park et al.

PROSTHETIC TREATMENT

The protocol for this CAD/CAM prosthesis is basically

same with the conventional method for implant retained

prosthesis2 except that the framework was going to be

milled from a one-piece block of titanium by means of a

computer numeric controlled (CNC) milling technique

(Procera Implant Bridge, Nobel Biocare, Goteborg,

Sweden).3 The master cast was fabricated from pick-up type

impression at the fixture level using open tray made with

individual verification indices luted together in patient’s

mouth using autopolymerizing resin (GC Pattern resin, GC

America, Inc., Alsip, IL, USA) and polyether (Impregum,

3M ESPE, St. Paul, MN, USA).4 One additional step to get

better precision and more predictability was to make an

accurate scan model served as the basis for the fabrication

of a titanium framework. This could be accomplished by

direct dipping of another luted verification indices into the

least expansion dental stone (0.08 % setting expansion,

Mounting Stone, Whip Mix, Louisville, KY, USA) without

taking impression (Fig. 3). A jaw relation record was made

for mounting the master cast, and the wax denture was tried

in patient’s mouth after tooth set up (Fig. 4-A). After

making stone index for tooth set-up (Fig. 4-B), prototype

for titanium framework was fabricated with pattern resin

within the space of boiled-out waxes (Fig. 5). The fitness of

this prototype was verified on scan model, and then scanned

(Procera Forte Scanner, Nobel Biocare, Goteborg, Sweden)

for sending information to a milling center of Nobel Biocare

Headquarters at Sweden via internet. Once a milled

titanium framework was received, the passive fit was

verified on the scan model (Fig. 6) and in the mouth with

the recommended screw test.5-7 Subsequent to the denture

tooth setup, esthetics, phonetics, and occlusion were

evaluated and final prosthesis was processed after titanium

surface treatments including mechanical retention groove,

and silicoating. The final rehabilitation of the edentulous

maxilla was rendered in the form of a screw-retained

maxillary metal-reinforced resin-based complete prosthesis.

For verification of seating, panoramic radiograph was taken

(Fig. 7).

DISCUSSION

In certain environments, it is almost impossible to

fabricate fixed implant-supported prosthesis without major

surgery, such as block bone graft and nerve repositioning. If

one could place implants without those kinds of surgeries,

then most likely face to difficulties in fabricating final

prostheses due to the angulations problem.

This patient having slanted occlusal plane, severe

generalized horizontal and vertical alveolar ridge resorption

in the maxilla is certainly a serious challenge for implant

placement and left little room for errors. Augmentative

procedures in the form of guided bone regeneration, ridge

split techniques, or block grafts would increase the

dimensions of the alveolar ridge, but would be associated

with multiple and invasive surgical procedures, significantly

prolonging treatment time and increasing treatment cost.

Surgical planning, converting into the stereolithographic

model, and preparing the bone-supported surgical templates

allowed the precise placement of 7 out of 8 planned

J Korean Acad Prosthodont 2008 Vol 46 No 6 635

Fig. 1. Computer-aided surgery design.

Fig. 2. Stereolithographic model and implant placement using surgical template.

The management of a complex implant case using CAD-CAM technology: A clinical report EJ Park et al.

636 J Korean Acad Prosthodont 2008 Vol 46 No 6

Fig. 3. Scan model fabrication. Fig. 4. Tooth set-up and stone index.

Fig. 5. Prototype for Ti framework.

Fig. 7. Final Prostheses.

Fig. 6. Ti framework.

implants having primary stability achieved at 35 Ncm in a

severely resorbed edentulous maxilla, without bone

augmentation. Although the fit of the several guides on the

bone surface was somewhat problematic and required a

wide extension of the mucoperiosteal flap, the SurgiGuide

provides an excellent tool for mastering challenging implant

cases. Nowadays, SAFE system from the same company,

which dosen’t need to be changed according to the drill

A

A

B

B

A

B

The management of a complex implant case using CAD-CAM technology: A clinical report EJ Park et al.

size, is available and more accurate surgery is possible.

Also, this system can be used for any kind of implant

system. In the case at hand, implant planned for left central

incisor area could not be inserted due to insufficient bone

width. Furthermore, implant on right central incisor

presented with relatively severe peri-implant bone loss

several months after insertion. The latter may have occurred

due to the severely resorbed alveolar ridge, leaving only

minimal bone width bucco-palatally to implant, and/or due

to biomechanical overload. However, the implant was

completely supported by bone both mesially and distally at

the time of placement owing to precise position guide by

SurgiGuide, and it could survive successfully by splinting

with other implants in passive way by means of PIB.

Though continuous follow-up is required, the implant

presents without bleeding on probing or signs of marginal

inflammation at prosthesis delivery.

Once the surgery part is finished, still there remains

prosthetic challenges such as waxing, casting, soldering,

and/or laser welding associated with their technologies. By

applying CAD/CAM technique to fabricate the final

prosthesis, those kinds of challenges have been eliminated.

This method can lower the prices of casting metal and

component, and the risk of oral corrosion is lowered since it

is the same material as used in implant fixture. Furthermore,

the fabrication process is less sensitive to manual

technique.3,8 The intraoral precision of the prosthesis in this

method is completely dependent on the accuracy of the

master cast. Therefore, it is very important to verify

impression accuracy, and in this case, scan model separate

to the master cast was made and used for confirming the

fitness of the framework. Since no impression material was

involved and the least expansion dental stone was used, this

scan model could be the most accurate reproduction of the

oral environment. Orthop et al. compared the clinical and

radiographic result of implant-supported fixed prostheses

with conventional lost wax technique and CNC milled

titanium framework, and found better fracture resistance

and fitness on titanium framework in a 5-year clinical

follow-up.9 Both of the frameworks have similar preload on

gold screws, and the preloads of the milled titanium

framework with acrylic resin or porcelain showed similar

preloads before and after veneering.10

To summarize, the CAD/CAM technologies in this article

have improved the implant surgery process by reducing

graft procedures, shortening the total treatment period, and

decreasing cost and surgery time. Meanwhile, the

restorative process has shown more accurate and efficient

result comparing with the conventional lost-wax technique.

Further clinical and laboratory research is required for long-

term result.

ACKNOWLEDGMENTSThe author would like to acknowledge Dr. Alexander L.

Schrott and Dr. John Da Silva from Harvard School of

Dental Medicine for their support and Mr. Thomas Peterson

from North Shore Dental Lab for the laboratory assistances.

REFERENCES

1. McGarry TJ, Nimmo A, Skiba JF, Ahlstrom RH, Smith

CR, Koumjian JH, Arbree NS. Classification system for

partial edentulism. J Prosthodont 2002;11:181-93.

2. Bra°nemark PI. Osseointegration and its experimental back-

ground. J Prosthet Dent 1983;50:399-410.

3. Jemt T, Back T, Petersson A. Precision of CNC-milled tita-

nium frameworks for implant treatment in the edentulous

jaw. Int J Prosthodont 1999;12:209-15.

4. Shor A, Goto Y, Schuler RF. Rehabilitation of the edentu-

lous mandible with a fixed implant-supported prosthesis.

Pract Proced Aesthet Dent 2004;16:729-36.

5. Jemt T. Failures and complications in 391 consecutively in-

serted fixed prostheses supported by Bra°nemark implants

in edentulous jaws: a study of treatment from the time of

prosthesis placement to the first annual checkup. Int J Oral

Maxillofac Implants 1991;6:270-6.

6. Tan KB, Rubenstein JE, Nicholls JI, Yuodelis RA. Three-

dimensional analysis of the casting accuracy of one-piece,

osseointegrated implant-retained prostheses. Int J

Prosthodont 1993;6:346-63.

7. Kan JY, Rungcharassaeng K, Bohsali K, Goodacre CJ,

Lang BR. Clinical methods for evaluating implant frame-

work fit. J Prosthet Dent 1999;81:7-13.

8. Ortorp A, Jemt T, Back T, Jalevik T. Comparisons of preci-

sion of fit between cast and CNC-milled titanium implant

frameworks for the edentulous mandible. Int J Prosthodont

2003;16:194-200.

9. Ortorp A, Jemt T. Clinical experiences of computer numer-

ic control-milled titanium frameworks supported by im-

plants in the edentulous jaw: a 5-year prospective study.

Clin Implant Dent Relat Res 2004;6:199-209.

10. Ortorp A, Jemt T, Wennerberg A, Berggren C, Brycke M.

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J Korean Acad Prosthodont 2008 Vol 46 No 6 637

THE MANAGEMENT OF A COMPLEX IMPLANT CASE USING

CAD-CAM TECHNOLOGY: A CLINICAL REPORT

Eun-Jin Park*, DDS, MMSc, PhD

Assistant Professor, Department of Dentistry, School of Medicine, Ewha Womans University

PURPOSE: The application of computer-aided technology to implant dentistry has created new opportunities for treatment planning,

surgery and prosthodontic treatment, but the correct selection and combination of available methods may be challenging in times. Hence,

the purpose of this case report is to present a combination of several computer-aided tools as approaches to manage complicated implant

case. MATERIAL AND METHODS: A 47 year-old female patient with severe dental anxiety, high expectations, financial restrictions

and poor compliance presented for a fixed rehabilitation. A CT scan with a radiographic template obtained with software (SimPlant,

Materialize, Leuven, Belgium) was used for treatment planning. The surgical plan was created and converted into a stereolithographic mod-

el of the maxilla with bone-supported surgical templates (SurgiGuide, Materialise, Leuven, Belgium), that allowed for the precise place-

ment of 7 implants in a severely resorbed edentulous maxilla. After successful osseointegration, an accurate scan model served as the basis

for the fabrication of a one-piece milled titanium framework using the Procera (Nobel Biocare, Gothenburg, Sweden) technology. The final

rehabilitation of the edentulous maxilla was rendered in the form of a screw-retained maxillary metal-reinforced resin-based complete pros-

thesis. RESULTS: Despite challenging circumstances, 7 implants could be placed without bone augmentation in a severely resorbed maxil-

la using the SimPlant software for pre-implant analysis and the SurgiGuide-system as the surgical template. The patient was successfully

restored with a fixed full arch restoration, utilizing the Procera system for the fabrication of a milled titanium framework.

KEY WORDS: Edentulous maxilla, Computer-aided surgery, Milled titanium framework

Corresponding Author: Eun-Jin Park

Dept. of Dentistry School of Medicine, Ewha Womans Univ.

911-1 Mok-6-dong, Yangcheon-gu, Seoul, Korea +82-2-2650-5042: e-mail, prosth@ewha.ac.kr

Article history

Received June 9, 2008 Last Revison July 4, 2008 Accepted July 21, 2008.

638 J Kor Acad Prosthodont 2008 Vol 46 No 6

CASE REPORT